1. Field of the Invention
The present invention relates to a card-edge connector and a card member for an electronic apparatus and more particularly to a card-edge connector and a card member allowing a minimum of defective contact to occur and allowing a minimum of impurities to deposit on the contact points of contacts.
2. Description of the Background Art
A conventional card-edge connector applicable to various electronic apparatuses is generally made up of a card member with a printed circuit board and a connector affixed to a board, which is included in an electronic apparatus. The card member includes a circuit board, a plurality of card-edge electrodes arranged on the circuit board, and solder resist surrounding the card-edge electrodes. The connector includes a housing for receiving the card member and contacts corresponding one-to-one to the card-edge electrodes.
The conventional card-edge connector described above is superior in electric characteristic to, e.g., a two-piece connector because the card member, which plays the role of one connector, does not have any contact and is relatively short as a contact.
Today, to meet the increasing demand for the dense arrangement of card-edge electrodes, a distance between nearby card-edge electrodes as small as 1 mm or below, e.g., 0.5 mm is required. In this respect, the above conventional card-edge connector has the following problems left unsolved. When the card member is shifted or inclined when inserted into the connector, the contact points of the contacts are shifted from the card-edge electrodes, failing to establish electrical, connection. Further, the card-edge electrodes cannot be extended to the edge of the circuit board for production reasons. In this condition, when the card member is inserted into the connector, the contact points of the contacts rub the surface of the circuit board or the solder resist. As a result, impurities are apt to deposit on the contact points of the contacts.
Technologies relating to the present invention are disclosed in, e.g., Japanese Patent Laid-Open Publication No. 7-231153.
A conventional card-edge connector is shown in FIGS. 1A and 1B. As shown, the card-edge connector is made up of a card member 40A and a connector 40B provided on a board, which is affixed to, e.g., an electronic apparatus not shown. The card member 40A includes a printed circuit, not shown, and an electrode portion 40C that adjoins one edge of the card member 40A. The electrode portion 40C includes a plurality of card-edge electrodes 42 formed on a circuit board 41. Solder resist 43 surrounds the card-edge electrodes 42. The edge of the circuit board 41, adjoining the electrode portion 40C, is formed with a taper 46. The card-edge electrodes 42, solder resist 43 and taper 46 are formed on both sides of the circuit board 41.
The connector 40B on the board side includes a housing 44 for receiving the card member 40A and contacts 45 corresponding one-to-one to the card-edge electrodes 42. The housing 44 is formed with guides 44a and 44b for guiding opposite side edges 41A and 41b of the card member 40A when the card member 40A is inserted into the housing 44.
When the card member 40A is inserted into the connector 40B, the guides 44a and 44b guide the side edges 41a and 41b of the card member 40A until the electrode portion 40C has been electrically connected to the connector 40B. As shown in FIGS. 2A and 2B, in the engaged condition, the contact points of the contacts 45 of the connector 40B get on the card-edge electrodes 42 of the card member 40A to thereby establish electrical connection.
The conventional card-edge connector 40 described above has the following problems when consideration is given to the current trend toward the dense arrangement of card-edge electrodes, e.g., a distance between card-edge electrodes as small as 1 mm or less, e.g., 0.5 mm.
First, as shown in FIG. 1A, when the card member 40A is inserted into the connector 40B, it is likely that the card member 40 is shifted or inclined because the side edges 41a and 41b of the card member 40A lack dimensional accuracy. As a result, the contact points of the contacts 45, FIG. 2B, are shifted from the card-edge electrodes 42 and caused to get on the solder resist 43 or the surface of the circuit board 41, failing to establish electrical connection. Further, assume that the card-edge electrodes 42 are densely arranged in the electrode portion 40C at a small pitch. Then, even if the card member 40A is inserted into the connector 40B in an accurate position, the card-edge electrodes 42 and contacts 45 are shifted from each other little by little as a distance from a reference position increases although they may be accurately aligned at the reference position. The contacts noticeably shifted from the card-edge electrodes 42 would miss the card-edge electrodes 42 and would thereby bring about defective contact.
Second, the card-edge electrodes 42 cannot be extended to the edge of the circuit board 41 for production reasons. In this condition, when the card member 40A is inserted into the connector 40B, the contact points of the contacts 45 rub the surface of the circuit board 41 or the solder resist 43. As a result, impurities are apt to deposit on the contact points of the contacts 45.